1. Field of the Invention
The present invention relates to a rotary printing press, and more particularly to an apparatus for automatically mounting a plurality of printing plates, each delivered to the side of a respective printing unit, on a plate cylinder at respective predetermined positions and for automatically removing each printing plate from the plate cylinder after use, the apparatus including an auxiliary apparatus adapted to rationalize the processing of fresh printing plate immediately before mounting on the cylinder and of the used printing plates immediately after removal from the cylinder.
2. Description of the Prior Art
Various apparatus for automatically mounting and removing printing plates on a plate cylinder at predetermined positions are disclosed in the applicant's Japanese Patent Laid-Open Publications Nos. 58-140254, 58-188657 and 60-216350, while an apparatus for automatically distributing the printing plates from a plate making chamber to the respective printing units is disclosed in the applicant's Japanese Patent Laid-Open Publication No. 60-52343.
Of the prior art publications mentioned above, Japanese Patent Laid-Open Publications Nos. 58-188657 and 60-73850 are directed to the apparatus of the type same as that disclosed in the present application. However, a problem with these prior apparatus is that a mechanical hand for directly retaining the printing plate during the mounting and removing thereof is too complex in construction for maintenance, thus often incuring troubles and hence impairing the efficiency.
Further, usually four rows of printing plates, two in each row, namely eight printing plates in all are mounted on a peripheral surface of the plate cylinder. To exchange the used printing plates for new ones, removing one used printing plate and then mounting one new printing must be repeated eight times. Specifically, for each exchange, the mechanical hand removes one used printing plate from the peripheral surface of the plate cylinder and then carries the removed printing plate to a plate discharging position, whereupon the mechanical hand moves to a plate introducing position to pick up one new printing plate and then brings the new printing plate onto the peripheral surface of the plate cylinder. this exchanging operation must be repeated eight times, which requires a long time and hence impairs the efficiency.